Pathomorphological features of acute respiratory distress syndrome in competing lung diseases: COVID-19 and sarcoidosis

The COVID-19 pandemic is a worldwide problem. The clinical spectrum of SARS-CoV-2 infection varies from asymptomatic or paucity-symptomatic forms to conditions such as pneumonia, acute respiratory distress syndrome and multiple organ failure. Objective was to describe a clinical case of SARS-CoV-2 infection in the patient with sarcoidosis and cardiovascular pathology developing acute respiratory syndrome and lung edema. Material and methods. There were analyzed accompanying medical documentation (outpatient chart, medical history), clinical and morphological histology data (description of macro- and micro-preparations) using hematoxylin and eosin staining. Results. Lung histological examination revealed signs of diffuse alveolar damage such as hyaline membranes lining and following the contours of the alveolar walls. Areas of necrosis and desquamation of the alveolar epithelium in the form of scattered cells or layers, areas of hemorrhages and hemosiderophages are detected in the alveolar walls. In the lumen of the alveoli, a sloughed epithelium with a hemorrhagic component, few multinucleated cells, macrophages, protein masses, and accumulated edematous fluid were determined. Pulmonary vessels are moderately full-blooded, surrounded by perivascular infiltrates. Signs of lung sarcoidosis were revealed. Histological examination found epithelioid cell granulomas consisting of mononuclear phagocytes and lymphocytes, without signs of necrosis. Granulomas with a proliferative component and hemorrhage sites were determined. Giant cells with cytoplasmic inclusions were detected — asteroid corpuscles and Schauman corpuscles. Non-caseous granulomas consisting of clusters of epithelioid histiocytes and giant Langhans cells surrounded by lymphocytes were detected in the lymph nodes of the lung roots. Hamazaki–Wesenberg corpuscles inside giant cells were found in the zones of peripheral sinuses of lymph nodes. In the lumen of the bronchi, there was found fully exfoliated epithelium, mucus. Granulomas are mainly observed subendothelially on the mucous membrane, without caseous necrosis. Histological examination of the cardiovascular system revealed fragmentation of some cardiomyocytes, cardiomyocyte focal hypertrophy along with moderate interstitial edema, erythrocyte sludge. Zones of small focal sclerosis were determined. The vessels of the microcirculatory bed are anemic, with hypertrophy of the walls in small arteries and arterioles. Virological examination of the sectional material in the lungs revealed SARS-CoV-2 RNA. Conclusion. Based on the data of medical documentation and the results of a post-mortem examination, it follows that the cause of death of the patient R.A., 50 years old, was a new coronavirus infection COVID-19 that resulted in bilateral total viral pneumonia. Сo-morbidity with competing diseases such as lung sarcoidosis and cardiovascular diseases aggravated the disease course, led to the development of early ARDS and affected the lethal outcome.